The concept of presence is becoming increasingly important with respect to the provision of a number of new compelling services including instant messaging and chat groups to provide an enhanced wireless user experience. U.S. Pat. No. 6,405,035 to Singh, entitled System and Method for Forwarding Messages to a Subscriber Device and U.S. Pat. No. 6,430,604 to Ogle et al., entitled Technique for Enabling Messaging Systems to use Alternative Message Delivery Mechanisms, for instance detail the relevant art.
However, the determination of a given wireless subscriber's presence status is difficult to ascertain in a mobile environment. Existing methods for determining a mobile subscriber's presence involve periodic polling mechanisms whereby the identifier of the mobile subscriber's mobile station is queried periodically in order to ascertain the presence of the said subscriber (i.e. whether the mobile station is on or off). U.S. Pat. No. 5,889,839 to Beyda et al., entitled System and method for providing Automated Message Notification in a Wireless Communication System, remains illustrative of that art. And indeed, while periodic polling mechanisms may work effectively for a small number of subscribers, the number of aggregate queries associated with large numbers of such subscribers (as, in the millions) will materially affect the operation of critical network elements in the mobile network such as the Home Location Register (HLR). Effectively precluding the efficacy of such mechanisms for the determination of presence where again large numbers of subscribers (including the entire subscriber base of a given mobile network) may be concerned.
Alternative mechanisms for determining presence involve the development of an application which is either installed or downloaded into a suitably equipped mobile station. The application resident in the mobile station would in turn notify a centralized presence server via a messaging sequence which is transported via a suitably supported air interface and network protocols at specific points in time (for example, when the mobile station is turned on). While the latter alleviates issues juxtaposed with a large number of queries associated with the period polling mechanisms, the lack of mobile stations which are suitably equipped with sufficient processing power and memory, in addition to operating systems which are conducive to the operation of supplementary applications on them as such, have precluded the widespread adoption of the mobile station application based mechanism for presence determination.
A third mechanism for determining presence involves the monitoring of communication links, typically Signalling System 7 (SS7) links, which carry messages necessary for the continued operation of mobility networks. Passive devices are typically installed on SS7 links to monitor for various mobility management messages which infer whether a given mobile subscriber is active or inactive. And, while the mechanism of inferring presence does not involve the injection of messages into a given network, it does involve a considerable outlay of infrastructure to facilitate the monitoring of the appropriate number of SS7 links. Additionally, for some scenarios the passive monitoring of mobility management messages may not provide an accurate indication of whether the phone has been deactivated (for example, in the scenario whereby the battery is removed from the mobile station).
U.S. Pat. No. 6,058,303 to .ANG.strom et al., entitled System and Method for Subscriber Activity Supervision, details art akin to that disclosed herein however the disclosed means of implantation is restricted to a GSM-based PLMN system. And additionally in consideration of the fact that it remains central to the scope and intent of the present invention to disclose a system and method which minimizes impact to the network infrastructure over and above that referred to in the former, and indeed the state of the art in general. As an example, the art disclosed by .ANG.strom et al., requires the use of a SMS-C in order to initiate a “SMS-probe” while the are disclosed herein does not make use of the SMS-C to invoke a notification trigger. Therefore, the technical means of implementation remain materially dissimilar to anyone versed thereof.
U.S. Pat. No. 6,178,322 to Creech, entitled Message waiting notification using ANSI-41 network messaging protocols provides art relating to the establishment of a message waiting notification capability between a given network node and the HLR. However, the disclosed art does not utilize existing messaging operations and parameters (as provided in IS-841 by means of example) and therefore requires the development and support of incremental messaging operations and parameters which may not be supported by existing core network infrastructure (e.g. HLRs).